Electrical transmission system



April 5, 1933- J. G. ACEVES 2,113,263

ELECTRICAL TRANSMISSION SYSTEM Original Filed April 28, 1951 2Sheets-Sheet 1 Fig.1.'

i 11 3 10 5 1i 6 1 6 I 15 8 V J. 6 Ac'ez/eS INVENTOR ATTORNEYS April1938. J. G. ACEVES 2,113,263

ELECTRICAL TRANSMISSION SYSTEM Original Filed April 28, 1931 2Sheets-Sheet 2 J /lceves INVENTOR ATTORNEYS Patented Apr. 5, 1938 UNITEDSTATES PATENT OFFICE ELECTRICAL TRANSMISSION SYSTEM Julius GourguesAceves, New York, N. Y., assign- -or to Revelation Patents HoldingCompany, New York, N. Y., acorporation of Delaware Application April 28,1931, Serial No. 533,396 Renewed February 3, 1934 31 Claims.

current variations of larger amplitude without appreciable distortion.

Another object of the invention is to provide an improved method ofcoupling a series of electron discharge devices in tandem withoutemploying an external grid bias on any of the stages.

Another object of the invention is to provide a repeater employing apluralityv of electron discharge devices in cascade wherein one ofsaidof a preceding tube and the grid 'of said preceding tube isconnected to the cathode of the succeedingtube together with means forlimiti'ngthe' normal plate current or the said succcedingtube.

A rther feature of the invention relates to an amplifier systememploying a plurality of cascaded electron discharge devices wherein thegrid of one device is connected directly to the cathode of a precedingdevice, together with mean'sfor maintaining said connected grid andcathode at substantially ground potential without substantiallyaifecting the amplifying powers of the system.

Another feature of the invention relates to an amplifying stageemploying an electron discharge device, the input circuit of said devicebeing provided with another electron discharge device which compensatesfor the grid loss of the first mentioned amplifier device, togetherwithmeans for limiting the normal plate current of the said,

device to a minimum value.

Another feature relates to the novel organization and arrangement ofelements and circuits which go to make up an efilcient amplifier systemcapable of operating without distortion, and

without employing so-called negative grid bias.

Other features and advantages not specifically enumerated will beapparent after a consideration of the following detail descriptions andthe appended claims.

Referring to the drawings:

Fig. 1 represents an amplifier circuit to which the invention isespecially well adapted. This circuit is of the type disclosed andclaimed in application Serial No. 394,172, filed September 21, 1929,patented May 22, 1934, No. 1,959,540;

Fig. 2 shows the circuit of Fig. 1 modified in accordance with theinvention to maintain the normal plate current of the second tube at alow value;

Fig. 3 shows substantially the same circuit as Fig. 2, and in additionshows in detail the method of energizing the filament cathode from adirect current source;

Fig. 4 shows the system of Fig. 2 with means for energizing the cathodesfrom an alternating current source; 7

Fig. 5 is a typical schematic circuit diagram showing the inventionapplied to a sound reproducing system.

Referring more particularly to Fig. 1, the numerals l and 2 representschematically audions, orelectron discharge devices 01' the typeemploying an electron emitting cathode, a control grid and a plate oranode. The cathode 3 of the device I is directly connected by aconductor I to the control grid 5 of the device 2, and similarly thecathode 6 of the device 2 is connected by a conductor I through an inputdevice or coil 8 to the control grid 9 of the device I. The operatingpotential for the anode Iii and the anode II is derived in accordancewith usual practice, from a direct current source i2, the positive endof which is connected to the said anodes and the negative end of whichis grounded. In 'ad- ,dition, there is a connection i3 between thenegative end of the source I! and the cathode 6 in accordance withstandard practice. In other words, the output circuit of the device 2comprises the anode il, theprimary winding ll of an output transformersource I2 and cathode 6. The input circuit for said device 2 comprisesgrid 5, conductor 4, cathode 3, the electron stream between members 3and Ill, conductor I5, source i2, cathode G. In other words the inputcircuit for the device 2 includes the electron stream between thecathode 3 and the anode ID. This electron stream is adapted to be variedin accordance with well known principles by the control grid 9, whichhas its potential varied Y by the input element 9;as described in saidapplication, Serial No. 394,172. The variations in potential of the grid9.are repeated as corresponding charges on the grid 5. One explana-'tion. for this-, 'repeating action may be that as the grid 9 varies, thenumber of electrons leaving the fllament'fo r the plate It,correspondingly Q vary, and therefore the charge or potential conditionof the cathode I will follow the potential changes in the grid 9.Similarly the. potentials of-grid 5 corresponding to the potentials ofgrid 9 vary the electron stream between members 6 ,and II, andthus-control the current in the output circuit o f-the device}.

As described in said application, the grid 5 requires no externalnegative bias to enable the said device 2 to amplify the impressedpotentials witlr'inaximum faithfulness. In other words.

even though the grid 5 should swing positively there would be nodisproportion in the plate current as compared with the plate currentproduced when the said grid 5 should swing an equal amount negatively.As a matter of fact,

with the particular circuit arrangement shown in Fig. l, the grid 5 isat alltimes essentially positive with respect to the associated cathode6, regardless of the potential vvariations on the grid 9. i

Under these conditions therefore, there is a relatively" high normalplate current flowing through the output circuit of the device 2.

In otherwords, the main average potential of the grid 5 with respect tothe cathode 6 is relatively high and positive. The average normal plate-'current corresponding to this average positive ing and materiallyreducing the normal plate current of the device 2 without materiallyaffecting the amplifying powers of the system. In Fig. 2 thecorresponding elements to those of Fig. 1 are designated by the samenumerals. From an inspection of Fig. 2 it will be noticed that the onlydifference is that the connection 4' between the cathode 3 and the grid5 is connected to ground through a reactance coil It. If the call I 6 isof an extremely low ohmic resistance, then the grid 5 may be consideredto be practically at ground potential when no alternating E. M. F.s areimpressed on the grid 9.

In other words, the normal current from source l2 divides, one portionpassing from the positive pole of source l2, conductor l5, anode HI,cathode 3, high reactance l6, to the negative pole of the source l2. Atthe point I! the current divides and part flows to the grid 5, cathode6, and returning to the negative end of the source l2. However, sincethe ohmic resistance of the reactance I6 is vanishingly small, thepotential drop. thereacross will be substantially negligible and thegrid 5 will remain at substantially ground potential.

When an alternating E. M. F. is impressed 1 acteristic required for thesystem as a whole.

upon the grid 9 there is produced a corresponding change in the electronstream between elements 3 'and Ill. Preferably the inductance of coil I6 is so large'that for the lowest impressed amazes frequency itsreactive impedance is greater than the plate-cathode impedanee'of thedevice I. Under these conditions, therefore the reactive voltagedeveloped by the passage of the signal -variations through the coil Hiwill be applied directly between the grid 5 and the cathode 5. and willproduce corresponding changes in the output circuit of the device 2.

Although Fig.2 of the drawings shows the grid 5 at substantially groundpotential under normal conditions, it will-be understood that'the normalpotential of the grid 5 may be at any value determined by the desirednormalcurrent' 'in the output'circuit of device 2.-- Thus a suitablesource of steady potential may be inserted between the coil l9 and theground, although satisfactory operation is secured without such externalpotential, and the circuit of Fig. 2 may be arranged to provide anyfrequency-gain char- For example, the' coil 15 may be provided with anyother form of reacta'nce or resistance in shunt and/or in series.therewith in order to obtain different voltage drops for the variousfrequencies, or if desired, these additional reactances may be used forthe purpose of controlling the phase angles between the variousimpressed frequencies.

For example, a resistance connected in parallel "with the coil Itprovides a simple and eil'lclent method of obtaining uniform gain at allaudio frequencies. It will be understood, of course, that the circuit ofFig. 2 may be used for the transmission of any range of frequencies,

for example, if the system is designed to transmit audio frequenciesthen the coil I 6 will be designed to have an extremely low ohmicresistance, but a high reactance to the audio frequencies. Similarly, ifthe system is to be used for the transmission of radio frequencies, thecoil It will likewise havevery low resistance, but will have highreactance to the radio frequencies.

While the circuit of Fig. 1 shows the output load representedschematically by a load resistance, it will be understood that thisis-purely illustrative and that instead of a resistance load,

any other type of load my be employed and this load circuit may becoupled to the tube 2 in any other manner than by transformer couplingas shown.

While Fig. 2 does not show the particular circuits for rendering thecathodes 3 and 6 emissive, it will be understood that any suitablefilament heating circuit ,may be employed.

For example, Fig. 3 shows a circuit arrangement whereby the same currentused for the anode supply may be used for heating the iila-- ments. Thecurrent supply conductors it are adapted to be connected to a suitablesource of direct current and resistances I9 and 20 may be connected inseries with the cathodes 3 and 6 .to provide the proper value of currentfor heating these filaments. In addition it may be found desirable toemploy a pair of high reactance coils 2| and 22 in circuit with bothlegs of the filament 3, in place of a single reactance such asschematically shown in Fig. 2. The reactance coils 2| and 22 may be onseparate cores, or if desired, they may be wound on' a single coreprovided that the twoiwindiugs 2| and 22 are connected in such adirection that they will aid each other for alternating currents, andoppose each other for direct currents, and preferably, al-

though not necessarily, the same number of turns may be employed on eachcoil.

With the circuit arrangement of Fig. 3 it is preferred to employ, forthe tube I, an audion which requires low filament current, and has a lowamplification factor. For example, one type of tube that has been foundsuccessful for this purpose employs a filament current of 0.06 amp.

and has an amplification factor of 3.5.

a/case the heater filament 23 and the electron filament are connected inparallel with the secondary winding 25 of a filament supply transformerwhose primary winding 26 is connected to a suitable .source ofalternating current. The direct connection between the cathode 24 andthe grid 5 is maintained at substantially ground potential, it beingconnected to ground thru the high reactance, low resistance coil I6 asabove described. The grid return for the tube 2 is preferably, althoughnot necessarily, effected to the midpoint of the transformer winding 25in accordance with usual practice. The operation of the circuit of Fig.4 is substantially the same as that described in connection with Fig. 2.and further description thereof is not believed necessary at this point.

Fig. 5 shows a typical circuit arrangement embodying the invention in asound reproducin system. In this figure the numeral 21 represents asound record of any well known type, which by means of the pick-updevice 28, is translated into corresponding potential variations. Thesepotential variations are impressed upon the grid cathode circuit of theaudion 29, the output circuit of which is coupled, by means of thetransformer 30, to the input circuit of the tube 3| which correspondsto-the tube I of Figs. 1 to 4 inclusive. The amplified variationsimpressed upon the grid 32 of device 3| are repeated to the grid 33 ofthe audion device 34 in the manner set forth in application Serial No.394,172. The grid is likewise connected through the high reactance coil35 to the conductor 36, which may be at ground or other selected fixedpotential for the purpose of limiting or controlling the normal platecurrent in the device 3|. as hereinabove described. The grid 33therefore responds to the potential drops 'across the reactance 35, andcorrespondingly varies the output of the tube 34, which is coupled by asuitable output circuit to the sound reproducing device 31. While thesource of potential for the anodes and cathodes of the respective tubesis not shown in Fig. 5, the manner of connecting these sources to therespective electrodes is in accordance. with standard practice, and nodescription thereof is believed necessary.

While Figs. 1 to' 5 show the invention embodied in two separate audionshaving their grids and cathodes directly interconnected, it will beunderstood that the invention rnay also be practiced by combining thesaid audions in a single audion of the type disclosed in Patent No.2,002,207, May 21, 1935.

.While the invention has been disclosed in connection with specifictypes of electron discharge devices, and associated apparatus, it willbe understood that the invention is not limited thereto, but may bepracticed with other well known forms of apparatus without departingfrom the spirit and scope of the invention. One of the importantadvantages of applicants specific circuit arrangements is that-thevariation in potential of the first grid with respect to its cathode isin phase with the variations in potential of the second grid withrespect to its cathode. In other words, as an incoming signal raises thepotential of the grid 1 with respect to its cathode 3, there is acorresponding increase in potential applied across the grid 5 and thecathode 6, so that as the grid 9 swings positively with respect to itscathode 3, likewise the grid 5 swings positively with respect to itscathode 5. In this sense, therefore, the variations of grid potentialswith respect to the associated cathodes are in phase.

What is claimed is:

1. In a wave transmission system a first electron discharge device, asecond electron discharge device, a high-reactance coil connected inshunt to the grid-cathode of the first device and the grid-cathode ofthe second device, one terminal of said reactance coil being connectedto ground for maintaining the grid of the second device at or nearground potential when no signals are being transmitted.

2. In a wave repeating system a series of electron discharge deviceswith the grid of one device directly connect-ed to the cathode of apreceding device, and reactance means for maintaining the grid of saidsecond device at substantially ground potential when no signals arebeing repeated.

3. In a transmission system the combination of a first electrondischarge device, a second electron discharge device, each device havinga gridcathode input circuit, means common to both said input circuitsand connecmd in series with the grid-cathode of the first device tolimit the normal plate current of the second device, and circuitarrangements for allowing said second device to operate with a positivestatic bias on the grid without causing distortion in the output.

4. In an amplifying system the combination of a first electron dischargedevice, a second electron discharge device, a high reactance connectedin common to the grid-cathode circuits of each of said devices, andcircuit arrangements for impressing signal variations on the grid of thefirst device so that variations in potential between the grid of thefirst device and the cathode of the second device are in phase with thevariations in potential between the grid and cathode of the seconddevice.

5. A combination according to claim 4 in which the high reactance haslow ohmic resistance.

6. In an amplifying system the combination'ol a first electrondischarge. device, a second electron discharge device, the cathode ofsaid first device.

being directly connected to the grid of said second device, andthecathode of said second device being connected in a direct currentcircuit to the grid of said first device, means for limiting the normalanode currents of said second device, and circuit arrangements forimpressing signal variations on the grid of the first device so thatvariations in potential between the grid of the first device and thecathode of the seconddevice are in phase with the variations inpotential between the grid and cathode of the second device.

'7. The combination according to claim 6 in which the meansfor limitingthe anode current of the second device includes a high reactance betweenthe grid of said second device and the cathode thereof.

8. In an amplifier system a first electron discharge device, a secondelectron discharge device,

a source of anode potential for said second device, a connection betweenthe grid of said second device and the positive terminal of said source,said connection including the cathode-anode space of the first. device,means for limiting the normal anode current of the second device when nosignals are being transmitted. and circuit arrangements for impressingsignal variations on the grid of the first device so that variations inpotential between said grid and the cathode of the second device are inphase with the variations in potential between the grid and cathode of.the second device.

9. A system according to claim 8 in which the -means for limiting thenormal anode current in-- cludes a low resistance high reactance elementconnected between the grid of said second device and ground, said groundbeing at a negative pole of the anode supply.

10. In an amplifier system the combination of I a first electrondischarge device, a second electron discharge device, each of saiddevices having a cathode, a control grid and an anode, a low resistancehigh reactance element, the cathode of the first device being connectedto one terminal of said reactance and the grid of the first device andthe cathode of the second device being connected to the other terminalof said reactance.

13. A wave repeating system comprising a pair of electric dischargedevices each having cathode, anode and control electrodes, alow-resistance high-reactance connected in shunt to the cathode andcontrol electrode of the second device, and a signal input circuitconnected in series with said reactance across the cathode and controlelectrode oi. the first device.

14. A wave repeating system according to claim 13 in which one end ofsaid reactance is substantially at ground potential with respect to thesignal variations.

15. A wave repeating system according to charge devices with the load ofthe first device between the cathode and the negative terminal of theanode supply, a conductive path for maintaining the grid of the seconddevice at a predetermined static potential with respect to ground tolimit the normal anode current of said second device while allowing saidsecond device to operate with positive grid swing without causingdistortion. I

- 18. A wave repeating system comprising a pair of electric dischargedevices each having cathode,

anode and control electrodes, 8. signal input coil having one endconnected only to the grid of the first device, the other end of saidcoil being directly connected to the cathode of the second; device, anda high reactance direct current path connecting both said cathodes.

19. A wave repeating system comprising a pair of electric dischargedevices eachhaving anode, cathode and control electrodes, a directcurrent connection from the cathode of the first device to the grid of.the second device, and a highreactance impedance of relatively low ohmicresistance for maintaining the grid of the second device in theneighborhood of ground potential when no signals are being repeated.

20. A wave repeating system comprising 'a pair of electric dischargedevices each having'cathode, anode and control electrodes, a source ofanode potential having its positive pole connected to the anode of thefirst device and its negative terminal connected to the cathode of thesecond device, a direct current connection from the cathode of the firstdevice to the grid of the second device, and a high-reactance shuntingthe grid-cathode of the second device.

21. A wave repeating system comprising a pair of electric dischargedevices each having cathode, anode and control electrodes,means forimpressing signal variations. to be repeated across the grid of thefirst device and the cathode of the second device, a metallic connectionbetweenthe cathode of the first device and the grid of the second deviceto maintain the same phase rela tion between the signal variationsimpressed on both said grids, and an inductive reactance of low ohmicresistance connecting the cathode of the first device and thegrid of thesecond device to the negative terminal of the anode supply.

22. In a transmission system of the type employing two sets of electrondischarge elements each set comprising a cathode, anode and controlelectrode, a direct connection between the cathode oi the first set andthe control electrode of the second, means for limiting the normal anodecurrent of. the second set when no signals are being transmitted, saidmeans consisting of means for impressing signal variations on the'control electrode of the first set, said input means making a directcurrent path between the last mentioned control electrode and a negativepole of the said anode potential supply.

23. A combination according to claim 22 in which said means for limitingthe normal anode current comprises a resistance.

24. A combination according to claim 22 in which said means for limitingthe normal anode current comprises a reactance.

25. A combination according to. claim 22 in which the said negative poleof the anode supply is substantially at ground potential with respect tothe signals to be transmitted.

26. A combination according to claim .22 in which the said cathode ofthe second set of elements is substantially at ground potential withcathode of the first set and the control electrode of the second, meansfor limiting the normal anode current of the second set when no signalsare being transmitted, said means consisting of a direct current pathbetween the grid and cathode of the second set, an input circuitarrangement for impressing signal variations between the controlelectrode of the first set and the cathode of the control electrode ofsaid second valve; means including circuit connections for connectingthe anode circuits of said valves in parallel across said source; and achoke coil inserted in the cathode lead oifsaid first valve.

29. In an electrical system, a first thermionic valve; a secondthermionic valve, said valves having cathode grid and anode electrodes;a

source of anode potential; a direct conductive coupling connection fromthe cathode of said first valve to the grid of said second valve; meansincluding circuit connections for connecting the anode circuits of saidvalves in parallel across said source; and a resistance and a choke coilin series inserted in the cathode lead of said first valve.

30. In an electric system, a first thermionic valve; a second thermionicvalve, said valves having cathode grid and anode electrodes; a source ofanode potential supply; a direct conductive coupling connection from thecathode of said first valve to the grid of said second valve; meansincluding circuit connections for connecting the anode of circuits of.said valves in parallel across said source; impedance means inserted inthe cathode leads of said valves comprising a choke coil in the cathodelead of said first valve for maintaining predetermined operatingpotentials of said electrodes and for producing coupling potential forsaid second valve.

31. In a system as described in claim 30, at least one further directcurrent circuit extending from the positive pole 01 said source over thecathode of said second valve, to'the negative pole of said source.

JULIUS GOURGUES ACEVES.

, Disclaimer sron SYSTEM. Patent -ELEG'I'RICAL TRANSMIS- Disclaimerfiled Nov. 2,

1950, by the assignee, Remoo Electronic, Inc.

Hereb enters this disclaimer to claims 6, 22, 23, and 27 of said patent.

[ flioial Gazette December 5, 1950.]

cathode of the first set and the control electrode of the second, meansfor limiting the normal anode current of the second set when no signalsare being transmitted, said means consisting of a direct current pathbetween the grid and cathode of the second set, an input circuitarrangement for impressing signal variations between the controlelectrode of the first set and the cathode of the control electrode ofsaid second valve; means including circuit connections for connectingthe anode circuits of said valves in parallel across said source; and achoke coil inserted in the cathode lead oifsaid first valve.

29. In an electrical system, a first thermionic valve; a secondthermionic valve, said valves having cathode grid and anode electrodes;a

source of anode potential; a direct conductive coupling connection fromthe cathode of said first valve to the grid of said second valve; meansincluding circuit connections for connecting the anode circuits of saidvalves in parallel across said source; and a resistance and a choke coilin series inserted in the cathode lead of said first valve.

30. In an electric system, a first thermionic valve; a second thermionicvalve, said valves having cathode grid and anode electrodes; a source ofanode potential supply; a direct conductive coupling connection from thecathode of said first valve to the grid of said second valve; meansincluding circuit connections for connecting the anode of circuits of.said valves in parallel across said source; impedance means inserted inthe cathode leads of said valves comprising a choke coil in the cathodelead of said first valve for maintaining predetermined operatingpotentials of said electrodes and for producing coupling potential forsaid second valve.

31. In a system as described in claim 30, at least one further directcurrent circuit extending from the positive pole 01 said source over thecathode of said second valve, to'the negative pole of said source.

JULIUS GOURGUES ACEVES.

, Disclaimer sron SYSTEM. Patent -ELEG'I'RICAL TRANSMIS- Disclaimerfiled Nov. 2,

1950, by the assignee, Remoo Electronic, Inc.

Hereb enters this disclaimer to claims 6, 22, 23, and 27 of said patent.

[ flioial Gazette December 5, 1950.]

